It is common today to remove natural lenses which have been clouded with cataracts and implant artificial intraocular lenses in the eye substantially restoring the sight of the individual. In order to remove the cataractous natural lens of the eye and replace it with an intraocular lens, the integrity of the eye cavity must be breached. Eye surgery of this type is of a very sensitive nature, it requires incisions in corneal tissues and interior portions of the eye and may optically or otherwise affect the vision of the patient. It is advantageous when performing this surgery to use the smallest corneal incision possible which will allow the surgeon to accomplish the task of removing the necessary portions of the natural lens and insert a replacement intraocular lens. Generally, a smaller incision in the corneal tissue will create less trauma to the eye and reduce the possibility of post surgical complications.
The procedure for removal of the natural lens of the eye can be accomplished by the use of a relatively small incision. However, the implanting of intraocular lens implants of the past have required the use of a larger incision in the corneal tissue in order to allow the lens to pass through and be positioned in the posterior or anterior chamber of the eye.
Intraocular lenses of the past have generally been designed with a non-deformable lens body and flexible fixation elements extending from it which center and hold the lens in position in the eye. The incision necessary to insert such intraocular lenses is generally determined by the diameter of the nondeformable lens body of the implant (which typically is on the order of 6-8 mm in diameter). The fixation elements are normally flexible and can be folded over the lens body during insertion, or the lens implant can be rotated through the insertion.
More recently, lenses have been produced which have deformable optical zones and fixation elements which are deformed and inserted through a smaller incision in the ocular tissue of an eye and which will return to their original shape upon insertion into the eye. An example of lenses of this type is shown in U.S. Pat. No. 4,573,998, issued to Mazzocco. Typically, these foldable intraocular lenses are made from a silicone material.
Past apparatuses for insertion of intraocular lenses have included various instruments for holding of the lenses and inserting them through incisions into the eye. Instruments used for this purpose have ranged from common forceps, to configurations specifically designed to engage and hold a particular intraocular lens design for inserting the lens through the incision into the operative position in the posterior or anterior chambers of the eye. Examples of such prior art devices may be found in U.S. Pat. Nos. 4,122,556; 4,143,427; 4,170,043; 4,190,049; 4,198,980; 4,214,585; 4,429,421; 4,527,294; and 4,530,117.
Some apparatuses for insertion of deformable intraocular lenses are disclosed in the Mazzocco patent, U.S. Pat. No. 4,573,998. As disclosed therein, the deformable lenses may be deformed to smaller sizes by pulling or pushing them through incisions in the cornea by a hooklike tool, by sucking the lens through small openings in syringe-type tool, or by folding, rolling, or crushing the lenses into non-distinct shapes by the instruments as set forth therein. While these apparatuses and instruments may allow deformation and insertion of deformable intraocular lenses through small incisions in the eye, they have disadvantages in that they may damage the integrity of the lens implants or may release the lens implants in an undesirable or unknown position in the interior of the eye.
For instance, the hooking or otherwise pushing or stretching of the lens implant through the incision may cause damage to or tearing of the lens implant at the point of engagement between the hook and the edge of the lens. The use of a syringe arrangement may allow the lens implant to be released into the eye in any number of unknown positions, many of which may be undesirable and may require further entrance into the internal chambers of the eye to adjust the positioning of the lens implant. The forceps-type designs disclosed require compression of the lens into non-descript folded shapes which may damage the lens implant at creases in the folds. These creases may cause optical deformations in the lens and may even require further surgery to alleviate these problems. In addition, the apparatuses disclosed may cause problems in the releasing of the intraocular lens after the instrument is inserted into the eye cavity.